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Propagação e tipagem molecular de estirpes de Chlamydia trachomatis
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Resumo(s)
Chlamydia trachomatis, uma bactéria intracelular da família Chlamydiaceae, infecta exclusivamente a espécie humana. As clamídias são bactérias gram-negativas incapazes de sintetizar adenosina trifosfato, uma restrição metabólica que justifica a sua total dependência da célula hospedeira para obter energia. C. trachomatis constitui a principal causa bacteriana de infecções sexualmente transmissíveis em todo o mundo. Na ausência de tratamento, as infecções por C. trachomatis podem causar cervicite, doença inflamatória pélvica, gravidez ectópica e infertilidade tubária, na mulher, e no homem, epididimite. No presente estudo foi feita uma análise ao gene ompA de 297 espécimes de C. trachomatis. Os genótipos E, D e F (32,7%, 21,4% e 18,0%, respectivamente) predominaram relativamente aos restantes genótipos ompA de C. trachomatis (A, B, Ba, C, G, H, I, J, K e L1-3), representando cerca de três quartos das estirpes tipadas. Foram identificados dois casos de infecção pelo genótipo L2, indicando que estas estirpes causadoras de linfogranuloma venéreo circulam em Portugal. Em 40,5% das estirpes clínicas tipadas foram encontradas mutações pontuais no gene ompA, sendo os genótipos D (41,2%), G (21,0%) e I (19,3%) aqueles em que foi observado maior número de variantes. No decurso do presente estudo foi ainda possível propagar 25 estirpes
em cultura celular e implementar uma técnica de isolamento de clones de C. trachomatis.
O presente estudo constituiu um contributo para a vigilância epidemiológica que beneficiará da contínua monitorização da distribuição genotípica de C. trachomatis em diversas regiões geográficas com vista a uma melhor compreensão da infecção.
Chlamydia trachomatis belongs to the family Chlamydiaceae and is an intracellular bacterium that only infects humans. Chlamydiae are gram-negativebacteria that are incapable of adenosine triphosphate synthesis, a metabolic constraint that justifies their absolute energy dependence from the host cell. C. trachomatis is worldwide leading cause of sexually transmitted bacterial infections. Without treatment, C. trachomatis infections can cause cervicitis, pelvic inflammatory disease, ectopic pregnancy and tubal infertility in women, and epididymitis in men. In the present study the ompA gene of 297 C. trachomatis specimens was determined and analyzed. Genotypes E, D and F (32.7%, 21.4% and 18.0%, respectively) prevailed over the remainder C. trachomatis ompA genotypes (A, B, Ba, C, G, H, I, J, K e L1-3), accounting for about threequarters of all typed strains. Two cases of infection with genotype L2 were identified, indicating that these strains, which cause lymphogranuloma venereum, are currently circulating in Portugal. Point mutations in the ompA gene were found in 40.5% of the typed specimens, among which genotypes D (41.2%) G (21.0%) and I (19.3%) provided most of the variants. Along the study 25 C. trachomatis clinical strains were propagated in cell culture and the plaque assay technique for isolating chlamydial clones was implemented in the host laboratory. The present study is a contribution to the molecular epidemiological surveillance which would strongly benefit from a continuous monitoring of C. trachomatis genotypic distribution within different geographical regions in order to better understand the chlamydial infection.
Chlamydia trachomatis belongs to the family Chlamydiaceae and is an intracellular bacterium that only infects humans. Chlamydiae are gram-negativebacteria that are incapable of adenosine triphosphate synthesis, a metabolic constraint that justifies their absolute energy dependence from the host cell. C. trachomatis is worldwide leading cause of sexually transmitted bacterial infections. Without treatment, C. trachomatis infections can cause cervicitis, pelvic inflammatory disease, ectopic pregnancy and tubal infertility in women, and epididymitis in men. In the present study the ompA gene of 297 C. trachomatis specimens was determined and analyzed. Genotypes E, D and F (32.7%, 21.4% and 18.0%, respectively) prevailed over the remainder C. trachomatis ompA genotypes (A, B, Ba, C, G, H, I, J, K e L1-3), accounting for about threequarters of all typed strains. Two cases of infection with genotype L2 were identified, indicating that these strains, which cause lymphogranuloma venereum, are currently circulating in Portugal. Point mutations in the ompA gene were found in 40.5% of the typed specimens, among which genotypes D (41.2%) G (21.0%) and I (19.3%) provided most of the variants. Along the study 25 C. trachomatis clinical strains were propagated in cell culture and the plaque assay technique for isolating chlamydial clones was implemented in the host laboratory. The present study is a contribution to the molecular epidemiological surveillance which would strongly benefit from a continuous monitoring of C. trachomatis genotypic distribution within different geographical regions in order to better understand the chlamydial infection.
Descrição
Tese de mestrado em Biologia Humana e Ambiente, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2015
Palavras-chave
Chlamydia trachomatis Genotipagem ompA Cultura celular Epidemiologia molecular Variabilidade genética Teses de mestrado - 2015